Conventionally, anisotropic conductive film (ACF) is used as an adhesive film to electrically connect respective electronic components such as in connecting a liquid-crystal panel and an IC chip. This anisotropic conductive film is used, for example, to connect terminals of flexible print circuits (FPC) or IC chips to ITO (indium tin oxide) electrodes formed onto a glass substrate of an LCD panel and can be used both to bond and electrically connect a variety of respective terminals (for example, refer to PLT 1 and 2).
As an anisotropic conductive film, an epoxy resin type electrically insulating adhesive agent having conductive particles dispersed therein is generally used, for example, by conductive particles being trapped and deformed between a terminal of an IC chip and an ITO electrode of a glass substrate, the IC chip and the ITO electrode are electrically connected, and by curing the adhesive agent in this state, the IC chip and the ITO electrode are mechanically connected.
Such an adhesive film is formed onto a long and narrow release sheet and is shipped as a film roll wound around a reel in roll-form; at utilization time, the adhesive film is pulled off the reel and, after cutting to the needed length, used to connect electronic components.
At utilization time of a film roll, when unwinding an adhesive film from the reel, winding tension occurs. Stress caused by this winding tension increases towards the roll core. Furthermore, this stress increases along with increasing length of an adhesive film wound around a reel. In the case of this stress being too large, the adhesive agent component protrudes outside of the film roll and is deposited on flanges of the reel which causes blocking in which normal dispensing of the adhesive film from the reel is made impossible.
It is possible to prevent blocking by shortening the adhesive film to sufficiently reduce stress caused by winding tension of the film roll; however, this increases the frequency of reel replacement for which a line must be stopped each time, thus lowering productivity. Furthermore, while it may be possible to improve blocking properties by lowering adhesive force, this would adversely affect adhesive properties during temporary pressure bonding.